1. Field of the Invention
The present invention relates to a plating apparatus and method, and more particularly to a plating apparatus and method for filling interconnection grooves formed in a semiconductor substrate or the like with metal such as copper.
2. Description of the Related Art
Generally, aluminum or aluminum alloy has been surface of a semiconductor substrate. The higher integration of integrated circuits on the semiconductor substrate requires that a material having a higher electric conductivity should be used for interconnection circuits. Therefore, there has been proposed a method comprising plating a surface of a substrate to fill interconnection patterns formed in the substrate with copper or copper alloy.
Various methods such as chemical vapor deposition (CVD) process, sputtering process, and the like have been used to fill interconnection patterns formed in a substrate with copper or copper alloy. However, when a metallic layer on a substrate is formed of copper or copper alloy, i.e., when copper interconnections are formed on the substrate, the CVD process requires high cost, and, if an aspect ratio is high (i.e., the depth of the pattern is larger than the width), then it is difficult to fill the interconnection patterns with copper or copper alloy in the sputtering process. Therefore, the aforementioned plating method is most effective to fill interconnection patterns formed in a substrate with copper or copper alloy.
There are various methods for plating a surface of a semiconductor substrate with copper. For example, in a cup-type plating method, a dip-type plating method, or the like, a plating container always holds a plating solution, and a substrate is dipped into the, plating solution. In another plating method, a plating container holds a plating solution only when a substrate is fed into the plating container. Further, in an electrolytic plating method, an electric potential difference is applied to plate a substrate. On the other hand, in an electroless plating method, an electric potential difference is not applied.
A conventional plating apparatus for plating a substrate with copper in these methods comprises a plating unit for plating a substrate, and, in addition, a plurality of supplementary units such as a cleaning unit for cleaning and drying a plated substrate and a transfer robot horizontally disposed for transferring a substrate between these units. The substrate is transferred between these units. A predetermined process is performed in each of units, and then the substrate is transferred to a next unit.
However, with the conventional plating apparatus, since it is difficult to efficiently dispose units for plating a substrate or performing its supplementary process in one housing unit, the conventional plating apparatus requires a large space to be installed in order to continuously plate the substrate in the housing unit. Further, for example, when the substrate is plated in a housing unit having a clean atmosphere, chemicals used in the plating process are diffused as chemical mist or gas and hence attached to a processed substrate.
The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a plating apparatus and method which comprises a plurality of units (pieces of equipments) disposed efficiently in one housing unit for continuously plating a substrate, and can hence reduce a space to be installed, and can prevent the substrate from being contaminated with chemicals used in the plating process.
According to a first aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-treatment unit for pre-treating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-treated in the pre-treatment unit. A first substrate stage is disposed between the cassette stage and the pre-treatment unit for holding a substrate placed thereon. A cleaning and drying unit is disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with pure water and drying the substrate. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the first substrate stage, and a second transfer device transfers a substrate between the first substrate stage, the pre-treatment unit, and the plating unit.
With this construction, a substrate is pre-treated and plated after being taken out of the substrate cassette, and then cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
According to a second aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-treatment unit for pre-treating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-treated in the pre-treatment unit. A first substrate stage is disposed between the cassette stage and the pre-treatment unit for holding a substrate placed thereon, and a chemical liquid cleaning unit disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with chemical liquid. A cleaning and drying unit is disposed between the cassette stage and the chemical liquid cleaning unit for cleaning a plated substrate with pure water and drying the substrate, a second substrate stage is disposed between the chemical liquid cleaning unit and the cleaning and drying unit for holding a substrate placed thereon. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the second substrate stage, a second transfer device transfers a substrate between the first substrate stage, the pre-treatment unit, and the plating unit, and a third transfer device transfers a substrate between the first semiconductor stage, the chemical liquid cleaning unit, and the second substrate stage.
With this construction, a substrate is pre-treated and plated after being taken out of the substrate cassette, and then cleaned with chemical liquid. Thereafter, the substrate is cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
In a preferred aspect of the present invention, at least one of the first substrate stage and the second substrate stage comprises two substrate stages, and at least one of the two substrate stages in the at least one of the first substrate stage and the second substrate stage is constituted so as to place a substrate thereon and clean the substrate. With this construction, at least one of a plated substrate and a substrate cleaned with chemical liquid can be placed on and cleaned in the substrate stage having a cleaning function, and can then be transferred to a next unit.
In a preferred aspect of the present invention, the housing unit has a partition wall for dividing the housing unit into a plating section and a clean section. The plating section has the pre-treatment unit, the plating unit, the fist substrate stage, and the second transfer device therein. The clean section has another unit therein. The partition wall has a shutter for passing a substrate therethrough; air can individually be supplied into and exhausted from each of the plating section and the clean section, and the pressure of the clean section is controlled so as to be higher than the pressure of the plating section.
In the plating section, chemicals used in the pre-treatment and plating processes are diffused as chemical mist or gas. With the above construction, the plating section is separated from the clean section required to be clean, and measures against particles are taken in each of the sections. When the pressure of the clean section is controlled so as to be higher than the pressure of the plating section, the chemical mist or gas can be prevented from being attached to a processed substrate.
In a preferred aspect of the present invention, a container for accommodating a substrate for trial operation is disposed in the housing unit, and one of the transfer devices takes out the substrate for trial operation from the container and returns the substrate for trial operation to the container. This construction can eliminate contamination or lowering of the throughput caused by introduction of the substrate for trial operation from the outside when trial operation is conducted.
In a preferred aspect of the present invention, the container for accommodating a substrate for trial operation is disposed in the vicinity of the first substrate stage. The second transfer device takes out the substrate for trial operation from the container and returns the substrate for trial operation to the container. With this construction, trial operation using a substrate for trial operation can be conducted in such a manner that the substrate for trial operation is pre-treated, plated, cleaned and dried, and then returned to the container.
A plurality of plating units may be provided in the housing, and a plating solution may respectively be fed to each of the plating units from a plating solution regulating tank in a single plating process system. In this case, when a plating solution regulating tank having a large capacity is used in the process plating system, and the flow rate in each of the plating units is controlled, a variation in quality of the plating solution respectively fed to each of the plating units can be suppressed.
According to a third aspect of the present invention, there is provided a processing apparatus for processing a semiconductor substrate with chemical liquid or pure water, the processing apparatus comprising an inverting mechanism for inverting a semiconductor substrate.
According to a fourth aspect of the present invention, there is provided a plating apparatus for plating a surface of a semiconductor substrate. The plating apparatus comprises a pre-treatment unit for pre-treating a semiconductor substrate to be plated with chemical liquid or pure water, the pre-treatment unit having an inverting mechanism for inverting the semiconductor substrate, and a plating unit for plating a surface of the semiconductor substrate pre-treated in the pre-treatment unit. With this construction, the surface of the substrate is pre-treated with chemical liquid in such a state that the front surface of the substrate faces upwardly. Thereafter, the substrate is inverted so that the front surface of the substrate faces downwardly, and then transferred to the plating unit, in which the substrate can be plated by a face-down-type plating.
According to a fifth aspect of the present invention, there is provided a plating method for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating method comprises placing a substrate cassette accommodating a substrate on a cassette stage, transferring the substrate in the substrate cassette to a first substrate stage by a first transfer device, transferring the substrate on the first substrate stage to a pre-treatment unit from the first substrate stage by a second transfer device, transferring the substrate pre-treated in the pre-treatment unit to a plating unit by the second transfer device, and transferring the substrate plated in the plating unit to a cleaning and drying unit.
According to a sixth aspect of the present invention, there is provided a plating method for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating method comprises placing a substrate cassette accommodating a substrate on a cassette stage, transferring a substrate in the substrate cassette to a first substrate stage by a first transfer device, transferring the substrate on the first substrate stage to a pre-treatment unit from the first substrate stage by a second transfer device, transferring the substrate pre-treated in the pre-treatment unit to a plating unit by the second transfer device, transferring the substrate plated in the plating unit to the first substrate stage by the second transfer device, transferring the substrate on the first substrate stage to a chemical liquid cleaning unit from the first substrate stage by a third transfer device, transferring the substrate cleaned with chemical liquid in the chemical liquid cleaning unit to the second substrate stage, and transferring the substrate on the second substrate stage to a cleaning and drying unit from the second substrate stage.
According to a seventh aspect of the present invention, there is provided a plating unit having a plating process container, the plating process container comprises a plating container having a plating chamber therein for holding a plating solution in the plating chamber, the plating chamber having an anode at its bottom. A plurality of plating solution supply nozzles eject the plating solution toward the central portion of the plating chamber. A regulating ring is provided in the vicinity of the peripheral portion of the plating chamber. A first plating solution discharge port discharges the plating solution in the plating chamber from the bottom of the plating chamber, and a second plating solution discharge port discharges the plating solution overflowing the peripheral portion of the plating chamber.
With this construction, the plating solution ejected from the plating solution supply nozzles into the central portion of the plating chamber collides at the central portion of the plating chamber to form an upward flow and a downward flow. The upward flow pushes up the liquid surface of the plating solution, and the downward flow pushes away peeled pieces of a black film formed on the surface of the anode. Thus, air bubbles can be prevented from remaining between the substrate and the liquid surface of the plating solution, and the black film can simultaneously be prevented from being attached to the surface of the substrate.
In a preferred aspect of the present invention, the anode is held by an anode support detachably mounted on the plating container. In this case, the anode can easily be attached to and detached from the plating container via the anode support to thus facilitate maintenance and replacement of the anode, and the like.
A labyrinth seal comprising a plurality of grooves arranged in parallel may be provided on at least one of the anode support and the plating container around the inlet of the anode support. Such a labyrinth seal can ensure reliable sealing of a gap between the plating container and the anode support to thus prevent the plating solution from leaking out.
An inert gas introduction passage for introducing inert gas and a plating solution return passage for discharging the plating solution remaining within the grooves may be connected to at least one of the grooves. When the plating solution remains within the grooves constituting the labyrinth seal, an inert gas is introduced to the grooves through the inert gas introduction passage, and hence the plating solution remaining within the grooves can be discharged to the exterior through the plating solution return passage.
According to an eighth aspect of the present invention, there is provided a plating unit comprising a rotatable housing having a substrate holding member provided at the lower end thereof, the substrate holding member projecting radially inwardly and abutting a peripheral portion of a substrate to hold the substrate. A pressing member is disposed in the housing for pressing the peripheral portion of the substrate against the substrate holding member to hold the substrate, the pressing member being rotatable together with the housing.
With this construction, a substrate can be transferred to the pressing member from a robot arm or the like in such a state that the pressing member is raised, and then the pressing member can be lowered. The peripheral portion of the substrate is held between the pressing member and the substrate holding member of the housing, and hence the substrate can be raised to be rotated in this state.
In a preferred aspect of the present invention, a plurality of air vent holes are formed in the substrate holding member provided at the lower end of the housing. In this case, air bubbles between the substrate and the liquid surface of the plating solution can easily be discharge through the air vent holes to the exterior.
In a preferred aspect of the present invention, the pressing member comprises a chuck mechanism disposed at the peripheral portion thereof for detachably holding the substrate on the lower surface of the pressing member.
In a preferred aspect of the present invention, a contact for a cathode electrode is disposed on the substrate holding member of the housing, and a feeding contact is disposed at the outer circumferential side of the pressing member. The contact for the cathode electrode is energized when a substrate is held by the substrate holding member and the pressing member. The feeding contact energizes the contact for the cathode electrode when the pressing member is lowered to bring the contact for the cathode electrode into contact with the feeding contact. In this case, since the plating solution is reliably sealed by the substrate holding member, the plating solution can be prevented from being brought into contact with the contact for the cathode electrode and the feeding contact.
According to a ninth aspect of the present invention, there is provided a plating unit comprising, a head having a rotatable housing, a vertically movable pressing member housed in the housing, and a substrate holding member disposed in the housing for holding a peripheral portion of a substrate between the pressing member ring and the substrate holding member. A plating process container is disposed below the head for holding a plating solution so that the liquid surface of the plating solution has a liquid level for plating which is higher than a position of a substrate held by the housing, and a liquid level for transferring the substrate which is lower than a position of a substrate held by the housing.
According to a tenth aspect of the present invention, there is provided a plating unit comprising, a head having a rotatable housing, a vertically movable pressing ring housed in the housing, and a substrate holding member disposed in the housing for holding a peripheral portion of a substrate between the pressing ring and the substrate holding member. A plating process container is disposed below the head for holding a plating solution so that the liquid surface of the plating solution has a liquid level for plating which is higher than a position of a substrate held by the housing, and a liquid level for transferring the substrate which is lower than a position of a substrate held by the housing.
According to an eleventh aspect of the present invention, there is provided a plating unit comprising, a head having a rotatable housing, a clamp mechanism with a swing link housed in the housing, the swing link being swingable in the horizontal direction, and a substrate holding member disposed in the housing for holding a peripheral portion of a substrate between the swing link and the substrate holding member. A plating process container is disposed below the head for holding a plating solution so that the liquid surface of the plating solution has a liquid level for plating which is higher than a position of a substrate held by the housing, and a liquid level for transferring the substrate which is lower than a position of a substrate held by the housing.
According to a twelfth aspect of the present invention, there is provided a plating unit comprising a head having a rotatable housing, the housing having an elastic member therein elastically deformable by pneumatic pressure, and a substrate holding member disposed in the housing for holding a peripheral portion of a substrate between the elastic member and the substrate holding member; and a plating process container is disposed below the head for holding a plating solution so that the liquid surface of the plating solution has a liquid level for plating which is higher than a position of a substrate held by the housing, and a liquid level for transferring the substrate which is lower than a position of a substrate held by the housing.
According to a thirteenth aspect of the present invention, there is provided a plating unit comprising, a head having a rotatable housing, the housing having a substrate holding member for holding a substrate, and a plating process container disposed below the head for holding a plating solution so that the liquid surface of the plating solution has at least two levels.
With this construction, the mechanism of the head can be simplified and compact. In addition, the plating process is carried out when the plating solution within the plating process container is at a liquid level for plating, while the substrate is dewatered and transferred when the plating solution is at a liquid level for transferring the substrate.
A contact for a cathode which is energized to the substrate when the substrate is held by the substrate holding member may be provided on the upper surface of the substrate holding member of the housing.
A substrate centering mechanism for performing centering of a substrate may be provided on the inner circumferential surface of the housing above the substrate holding member. A substrate is held by a transfer robot or the like, is carried into the housing, and is placed on the substrate holding member. In this case, when holding of the substrate by the transfer robot or the like is released, the centering of the substrate can be carried out.
The substrate centering mechanism may comprise a positioning block having a tapered inner surface which is widened outwardly in the upward direction, an elastic member for inwardly urging the positioning block, and a stopper for restricting an inward movement of the positioning block. While a substrate is guided by the tapered surface, the substrate is urged inwardly by the elastic member, thereby carrying out the centering of the substrate. With this construction, a substrate is held by a transfer robot or the like, is carried into the housing, and is placed on the substrate holding member. In this case, when the center of the substrate deviates from the center of the substrate holding member, the positioning block is rotated outwardly against the urging force of the elastic member and, upon the release of holding of the substrate by the transfer robot or the like, the positioning block is returned to the original position by the urging force of the elastic member. Thus, the centering of the substrate can be carried out.
According to a fourteenth aspect of the present invention, there is provided a plating unit comprising, a head having a substrate holding member for holding a substrate, a plating process container disposed below the head for holding a plating solution, and a plating solution suction mechanism for removing plating solution remaining at a portion abutting the peripheral portion of a substrate at the inner circumferential end of the substrate holding member.
The plating solution is likely to be left at a portion abutting the peripheral portion of a substrate at the inner circumferential end of the substrate holding member. With this construction, the plating solution remaining at the abutting portion is forced to be removed, thereby preventing the plating solution from being dried and becoming a source for particles.
A plating solution suction nozzle constituting the plating solution suction mechanism may extend in an arc form along the inner circumferential surface of the substrate holding member and be vertically and horizontally movable. With this construction, the plating solution left in the tip end of the annular projecting portion of the substrate holding member can be sucked and removed in a short time with high efficiency.
According to a fifteenth aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-plating unit for pre-plating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-plated in the pre-plating unit. A first substrate stage is disposed between the cassette stage and the pre-plating unit for holding a substrate placed thereon. A cleaning and drying unit is disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with pure water and then drying the substrate. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the first substrate stage, and a second transfer device transfers a substrate between the first substrate stage, the pre-plating unit, and the plating unit.
With this construction, a substrate is pre-plated and plated after being taken out of the substrate cassette, and then cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
According to a sixteenth aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-plating unit for pre-plating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-plated in the pre-plating unit. A first substrate stage is disposed between the cassette stage and the pre-plating unit for holding a substrate placed thereon. A chemical liquid cleaning unit is disposed between the cassette stage and the first substrate stage for cleaning a plated substrate with chemical liquid. A cleaning and drying unit is disposed between the cassette stage and the chemical liquid cleaning unit for cleaning a plated substrate with pure water and then drying the substrate. A second substrate stage is disposed between the chemical liquid cleaning unit and the cleaning and drying unit for holding a substrate placed thereon. A first transfer device transfers a substrate between the substrate cassette, the cleaning and drying unit, and the second substrate stage, a second transfer device transfers a substrate between the first substrate stage, the pre-plating unit, and the plating unit, and a third transfer device transfers a substrate between the first semiconductor stage, the chemical liquid cleaning unit, and the second substrate stage.
With this construction, a substrate is pre-plated and plated after being taken out of the substrate cassette, and then cleaned with chemical liquid. Thereafter, the substrate is cleaned with pure water and dried. Thus, a series of the processes can be performed continuously and efficiently in one housing unit, and hence the plated substrate can successively be transferred to a next unit.
According to a seventeenth aspect of the present invention, there is provided a plating apparatus for continuously plating a surface of a substrate with metal and performing its supplementary process in one housing unit. The plating apparatus comprises a cassette stage for placing a substrate cassette thereon, the substrate cassette accommodating a substrate, a pre-treatment unit for pre-treating a surface of a substrate, and a plating unit for plating a surface of the substrate pre-treated in the pre-treatment unit. A first substrate stage holds a substrate placed thereon. A cleaning and drying unit cleans a plated substrate with pure water and dries the substrate. A first transfer device transfers a substrate, and a second transfer device transfers a substrate. The housing unit has a partition wall for dividing the housing unit into a plating section and a clean section. The plating section has at least the pre-treatment unit, the plating unit, the fist substrate stage, and the second transfer device therein. The clean section has another unit therein, and the pressure of the clean section is controlled so as to be higher than the pressure of the plating section.
In a preferred aspect of the present invention, the first substrate stage comprises two substrate stages, and at least one of the two substrate stages in the first substrate stage is constituted so as to place a substrate thereon and clean a substrate.
In a preferred aspect of the present invention, a container for accommodating a substrate for trial operation is disposed in the housing unit, and one of the transfer devices takes out the substrate for trial operation from the container and returns the substrate for trial operation to the container.
The above and other objects, features, and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings which illustrates preferred embodiments of the present invention by way of example.